1. Field of the Invention
The present invention relates to an X-ray generator and a method for adjusting the same.
2. Description of the Related Art
As an X-ray source at a laboratory level in single crystal structure analysis using X-rays, mainly Cu—Kα rays and Mo—Kα rays are used. The former is mainly used for the analysis of an organic compound and the latter is mainly used for the analysis of an inorganic compound Accordingly, in the case of, for instance, an X-ray diffractometer shared in the analysis of the organic compound and the analysis of the inorganic compound, an X-ray source of the X-ray generator needs to be changed, in accordance with samples of a user.
In the case of an X-ray generator which radiates X-rays from a surface of an anticathode (target) by colliding thermoelectrons emitted from a cathode (filament) against the anticathode, the material of the anticathode to be collided with thermoelectrons needs to be changed for changing the types of X-ray outputted.
As a method of changing the material of the anticathode against which the thermoelectrons collide, conventionally, it is a common practice to detachably form the anticathode on the X-ray generator in advance, and by changing the anticathode, multiple kinds of X-rays can be outputted with one X-ray generator.
However, it is generally not easy to make the anticathode of the X-ray generator an easily detachable structure. Especially, in the case of a rotary anticathode type X-ray generator to obtain large volume or high intensity X-rays, there are fundamental difficulties in making the anticathode itself an easily detachable structure, because a coolant must be circulated in the anticathode to cool the anticathode, the anticathode itself serves as a movable portion rotating at a high speed, the circumferences of the cathode and the anticathode are required to be a vacuum atmosphere, and so on. Even when such difficulties are overcome, there are still problems that changing work of the anticathode is complicated, and a manufacturing cost is significantly increased.
For this reason, the X-ray generator has been developed, in which a plurality of anticathodes are previously prepared, and the anticathodes against which thermoelectrons collide, are switched by moving the cathode that emits the thermoelectrons (see, for instance, Patent Document 1). This X-ray generator is provided with plural kinds of anticathodes on an anticathode unit and the cathode corresponding to the anticathode unit is installed so that it is movable along an arranging direction of the anticathode parts on the anticathode unit by an cathode moving mechanism. Then, by switching the anticathode parts, against which the thermoelectrons collide, by moving the position of the cathode, the types of X-rays outputted can be changed.
(Document 1) Japanese Patent Bulletin No. 2848944
For instance, when an optical element having a layer structure is arranged in a taking out route of the X-rays of an X-ray generator in order to make the X-rays irradiating a sample monochromatic, if the types of X-rays to be outputted is changed by moving the position of the cathode as described above, the direction of the X-rays coming from the optical element also changes. Therefore, the problem is that the above-described situation must be corrected on the side of the optical system such as a goniometer, and much time is spent for adjusting the optical system.